This invention relates to new compositions of matter which may be useful as plasticizers for polymeric materials. More particularly, the invention relates to a novel class of polymers which are capable of plasticizing a wide variety of both natural and synthetic polymers.
Plasticizers are an important adjunct to the utilization of polymeric materials in that they are widely incorporated in both natural and synthetic polymers to increase the workability, flexibility or distensibility of such materials. In addition, they are often used as extenders for polymeric materials. In the plasticization or extension of organic polymers, organic plasticizers are generally used which are usually moderately high molecular weight liquids or, occasionally, low-melting solids.
Though there is considerable debate as to the mechanism by which various plasticizers function. Most plasticizers for polymeric materials are of the solvent type, i.e. rather high boiling, normally liquid organic compounds which are chemically inert toward the polymers in which they are used, but in which the polymer swells or is at least partially soluble and will therefore be readily softened by intimate contact with the plasticizer. The most widely used solvent-type plasticizers include esters of carboxylic acids or phosphoric acid, hydrocarbons, halogenated hydrocarbons, ethers, glycols and sulfonamides.
In the selection of a plasticizer, it is of particular importance that the plasticizer exercise the effect for which it is intended without undue adverse effect on other properties of the polymeric material and that it be at least comparable in cost and preferably lower in cost than the polymer to which it is added.
A particular problem in the field of polymer plasticization has been the plasticization of rubbers which are to be exposed to high temperatures under oxidative conditions. Plasticizers for this application must be non-volatile, must be compatible with the base polymer and must maintain the flexibility of the rubber and preferably have antioxidant activity, all of which must be done without significant impairment of the other performance properties of the rubber.
A new class of compositions has been discovered which not only have the above-described capability to plasticize high temperature performance rubber, but also to improve the resistance of such rubber to oxidative deterioration. Furthermore, these compositions, which possess the versatility to plasticize and otherwise improve the properties of many polymeric materials, have exceptional resistance to hydrolysis.